JP3016573B2 - Image evaluation device for video tape recorder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image evaluation device of a video tape recorder used particularly in a broadcasting station or a production.

2. Description of the Related Art In recent years, automation has been promoted in broadcast stations and productions, but the evaluation of the image quality of a video tape recorder currently depends on human eyes.

A conventional example of this type is shown in FIG. In FIG. 5, 1
Represents a block of a reproduction system of a video tape recorder (hereinafter referred to as VTR), and includes a video cylinder 2, heads a and b, a head amplifier 3, a dropout correction circuit 4, a signal processing circuit 5, a video output terminal 6, and a system control circuit 7. have. Reference numeral 8 denotes a monitor television receiver (hereinafter abbreviated as monitor TV) connected to the video output terminal 6, and reference numeral 9 denotes a dropout counter connected to the dropout correction circuit 4.

In the above configuration, the RF signals obtained from the heads a and b of the video cylinder 2 are amplified by the head amplifier 3.

At this time, a low signal level sometimes occurs in the RF signal output, and this is generally called dropout. At this time, since the RF signal is missing, the RF signal passes through the dropout correction circuit 4 and is converted into a video signal by the signal processing circuit 5 in order to detect and correct the RF signal. However, the dropout correction circuit 4 generally uses the scanning lines before and after the horizontal scanning line to compensate for the missing portion. Mass dropout), the corrected image is extensive,
The image quality is remarkably deteriorated, and the evaluation of the image quality is performed by the human eyes and feeling using the dropout counter 9 and the monitor TV8.

Problems to be Solved by the Invention In the conventional configuration as described above, the evaluation criteria change when the person changes, and since the images must be constantly monitored, it is hard work for the person in charge, and often mass dropouts occur. I often missed the footage.

Further, since the dropout counter 9 detects the width and the number of the dropouts detected by the dropout correction circuit 4 over the entire range of the output of the RF signal, for example, when the dropout has a delicate size (width). Again,
It takes a lot of time because it requires time and effort to confirm and determine the location of occurrence.

In this way, the evaluation of image degradation due to dropout is often left to the judgment of experience, which has hindered automation of broadcast stations and production.

The present invention solves the above-described problem. By determining the evaluation standard of a reproduced image of a VTR based on data such as a detection position of a dropout and a size of the dropout, an image evaluation that anyone can easily and definitely evaluate an image. It is a primary object to provide a device.

It is a second object of the present invention to provide an image evaluation apparatus capable of distinguishing between a still image and a moving image and setting an image evaluation criterion based on the type of tape material.

Means for Solving the Problems In order to solve the above problems, an image evaluation device of the present invention includes a system control circuit of a VTR, a dropout detection circuit, and a dropout occurrence point detection circuit connected to an output of the system control circuit. A circuit, a drop-out evaluation circuit connected to the output of the drop-out occurrence detection circuit, the output of the drop-out detection circuit, and communication means for communicating with the host computer.

Further, a moving picture detecting circuit for discriminating between a moving picture and a still picture of a video output reproduced by the video tape recorder is provided, and an output of the moving picture detecting circuit is inputted to the dropout evaluating circuit.

Operation According to the above-described configuration, since the location where the dropout occurs is detected, and the quality (quality) of the image is determined based on the size (width) and the number of the dropout, anyone can easily evaluate the image.

Furthermore, by discriminating between moving images and still images, it is possible to set detailed image evaluation criteria depending on whether the tape material is a material with many moving images or a material with many still images, thus achieving more accurate image evaluation. it can.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an image evaluation apparatus according to an embodiment of the present invention, FIG.
In FIG. 1, components having the same reference numerals as those in the conventional example shown in FIG. 5 have the same components or perform the same operations.

In FIG. 1, reference numeral 10 denotes an image evaluation device, which includes a dropout occurrence point detection circuit 11, a moving image detection circuit 12, and a dropout evaluation circuit 13. The dropout occurrence point detection circuit 11 has a system control circuit 7 and a dropout point. The dropout detection unit of the correction circuit 4 is connected, the video output terminal 6 is connected to the moving image detection circuit 12, and
The dropout evaluation circuit 13 is connected to the dropout occurrence point detection circuit 11, the moving image detection circuit 12, and the dropout detection section of the dropout correction circuit 4. The output of the dropout evaluation circuit 13 is connected to the host computer 14.

Hereinafter, the operation of the above configuration will be described. When the VTR is in the reproducing state, signals output alternately for each field are obtained from the outputs of the heads a and b of the video cylinder 2 as shown in (b) and (c) of FIG. By switching this with a head switching signal as shown in FIG. 2A, a high-frequency output signal as shown in FIG. 2D is obtained. Here, a and b indicate the reproduction output of the a head and the b head, respectively. The high-frequency output in FIG. 2D corresponds to the output of the head amplifier 3. Usually, when a dropout occurs, the high-frequency output signal is lost. Is detected and corrected. Also, the number H
With respect to the dropout occurring over the horizontal line (1H), the corrected signal location can be easily recognized. However, this state was very conspicuous in the center of the image on the monitor TV8, but was less conspicuous in the peripheral portion of the screen or in a portion that was covered by overscan of the monitor TV8. This is due to the characteristics of the human eye, and the center of the screen tends to be watched, while the periphery of the screen tends to be not watched. Further, when the image is a moving image, there is a tendency to focus on a moving object.

Therefore, in the VTR reproduction state, for example, a vertical wide blanking pulse as shown in FIG. 2 (e) is obtained from the system control circuit 7 to determine whether the dropout occurs in the vertical wide blanking. It is configured so that it can be distinguished whether it has occurred in other places. For example, the shaded portion of the monitor TV image shown in FIG. 2 (f) belongs to other than the vertical wide blanking, and this portion is particularly a watched portion. For the parts other than the hatched part,
It is set to loosen the evaluation criteria. Of course, the same level may be used. Normally, this shaded area is 40
It is desirable to set it to about 90%.

The dropout evaluation circuit 13 mainly includes a dropout counter section, a dropout width measurement section, a display section, an evaluation determination section using a microcomputer, a communication section with the host computer 14, and the like.

When the information on the location of the dropout and the size (width) and number of the dropouts are input to the dropout evaluation circuit 13, the microcomputer compares the information with a preset evaluation value, evaluates it, and evaluates it. Display error details on the host computer
Data is sent to 14 by communication means.

The host computer 14 prints out this data or displays an error on the screen to inform the operator of the image evaluation result. Further, since the image evaluation device 11 also has a display unit, the contents of the error occurrence can be easily understood without looking at the screen of the host computer 14. When this error occurs, it can be more effectively notified to the operator by linking it with a sound generator such as a buzzer.

In the above description, the dropout occurrence location is detected only in the width of the vertical wide blanking. However, as shown in FIG. 3, image determination can be performed by further adding horizontal wide blanking. In FIG. 3, (a) is a high frequency output signal, (b) is a horizontal wide blanking pulse, and (c) is a monitor TV with vertical and horizontal wide blanking.
3 shows an image.

In this case, there is an effect that the evaluation criterion based on the vertical blanking described above can be determined in more detail.

Although a specific image evaluation method needs to be reset because the level changes depending on the broadcasting station or the production, this embodiment has an effect that once set, anyone can easily and definitely evaluate the image.

Next, the moving image detection circuit 12 that further improves the image evaluation will be described. An example of a specific circuit of the moving image detection circuit 12 is shown by functional blocks in FIG. In FIG. 4, 15 is an analog / digital (A / O) conversion circuit, and 16 and 17 are A
A frame memory and a one-frame delay circuit connected to the / D conversion circuit 15, and a frame memory 19 connected to the one-frame delay circuit 17 are comparison and judgment circuits connected to the frame memories 16 and 18. Normally, frame memory 16,1
8. The one-frame delay circuit 17, the comparison and determination circuit 19, and the like are controlled by a microcomputer to make a determination.

The operation will be described below. When a video signal is input, it is converted into a digital signal by the A / D conversion circuit 15. The converted signal is input to a frame memory 16, and the other signal is input to a frame memory 18 via a one-frame delay circuit 17. By comparing and judging the two signals, the comparison and judgment circuit 19 can judge that the image is a still image if they match and a moving image if they do not match. After judging a moving image and a still image in this way, by inputting it to the dropout evaluation circuit 13, the type of the tape material (whether the material has many moving images, the material having many still images, etc.)
Since the image evaluation criteria can be set finely, anyone can easily and definitely obtain an image evaluation.

Effect of the Invention As described above, according to the present invention, anyone can easily and definitely evaluate a VTR image based on the size and number of dropout occurrence location detection circuits and dropouts. There is something.

Further, the provision of the moving image detection circuit makes it possible to determine whether the image is a moving image or a still image. This makes it possible to finely set an image evaluation criterion based on the type of tape material, and furthermore, it is possible to easily and definitely evaluate an image.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image evaluation device of a VTR according to an embodiment of the present invention. FIG. 2 is a waveform diagram of a main part and a front view of a monitor TV screen for explaining the operation of the image evaluation device.
FIG. 5 is a main part waveform diagram and a front view of a monitor TV screen for explaining still another operation of the image evaluation apparatus. FIG. 4 is a block diagram showing an example of a moving image detection circuit of the image evaluation apparatus. It is a block diagram of a conventional image evaluation device. 1 VTR playback system 2 Video cylinder 4 Dropout correction circuit 5 Signal processing circuit 7 System control circuit 10 Image evaluation device 11
Dropout occurrence detection circuit, 12: Video detection circuit, 13: Dropout evaluation circuit, 14: Host computer, 15: Analog / digital conversion circuit, 16, 1
8 ... claim memory, 17 ... 1 frame delay circuit, 19
...... Comparison circuit.

Claims (2)

(57) [Claims] A video tape recorder system control circuit; a dropout detection circuit for detecting a dropout of a reproduction signal of the video tape recorder; a dropout occurrence point detection circuit connected to the system control circuit; An image evaluation device for a video tape recorder, comprising: a dropout occurrence detection circuit; a dropout evaluation circuit connected to the dropout detection circuit; and communication means for communicating with a host computer. 2. A moving picture detecting circuit for judging a moving picture and a still picture of a video output reproduced by a video tape recorder, wherein the moving picture detecting circuit is connected to an input section of a dropout evaluating circuit. Item 3. An image evaluation device for a video tape recorder according to Item 1.